For recent seasons, mlb.com is clearly only reporting games in which the pitcher actually appeared in the batting lineup. However, for earlier seasons, the batting statistics report all games.  At least, this is what Randy Johnson's totals imply.

The closest thing I can find in the Official Rules on this is from 10.21:

"When a player listed in the starting lineup for the visiting club is substituted for before he plays defensively, he shall not receive credit in the defensive statistics (fielding), unless he actually plays that position during a game. All such players, however, shall be credited with one game played (in "batting statistics") as long as they are announced into the game or listed on the official lineup card."

I know this doesn't directly apply to this discussion, but my reading of the rule suggests that the "games played" column in batting statistics is intended to be all games played, not just ones in which the player bats.  Further, being the starting pitcher in a game where the DH is used still results in you being "listed in the starting lineup," no?

But what rule 10 says, and what actually happens, are sometimes two different things. Don't ask me about rule 10.18(g). ;)

TT